We Now Know More About the Link Between Birth Control & Breast Cancer

Whether it's the pill, the patch, or a range of other products, millions of women today use hormonal contraceptives; so it's little surprise that a new study shows that those who take them have an increased risk of breast cancer.

While contraceptive drugs that contain oestrogen have always been suspected of increasing the likelihood of breast cancer, researchers had expected smaller doses of the hormone, often combined with the drug progestin, would be safer, said Lina Morch, an epidemiologist at Copenhagen University Hospital who led a study analysing the records of 1.8 million women in Denmark. "Yes, hormonal contraception may increase your risk for breast cancer, but the absolute risk of breast cancer is small". "It's 1.3 extra cases of breast cancer per 10,000 women per year using hormonal contraception".

Dr Chris Zahn, ACOG's vice president for practice activities, acknowledged a link between breast cancer risk and hormone use, but urged concerned women to consult a trusted medical provider before making changes.

They found that women taking estrogen/progestin birth control pills have about a 20 percent increased risk of breast cancer.

Compared to what the group of researchers found in one of their other papers-that using hormonal contraception was associated with a 300 percent increase in suicide risk-"it is a modest increase", said Dr. Øjvind Lidegaard, one of the authors of the paper and a gynecologist at the University of Copenhagen.

"No one should take (oral contraceptives) without careful thought, but the advantages in avoiding an unwanted pregnancy will usually more than outweigh the very slightly increased risk of breast cancer", said Ashley Grossman, emeritus professor of endocrinologyat Britain's University of Oxford. The women were followed for almost 11 years.

A hormone specialist at Brigham and Women's Hospital who deals with contraceptive issues says the study shouldn't alarm those taking oral contraceptives.

Many studies show that oral contraceptives can also reduce the risk for cancer of the ovaries, uterus and possibly the colon.

Despite the risk, women will continue to use the pharmaceuticals, Morch said. According to an editorial that accompanied the study in NEJM, birth control may actually be protective against cancer on the whole despite this increased risk for one type.

They include smoking, obesity, starting menstruation early, having children late in life or not at all and not breastfeeding.

"Estrogen has been the primary focus of breast cancer research in general, and so we know much more about it than we do progesterone", Gaudet said.

Today, most versions of the pill contain between 15 and 35 micrograms of estrogen, Gaudet said. Any woman's risk of breast cancer goes up as she gets older. But by the time a woman reaches 40, her probability of developing breast cancer in the next 10 years is 1.45 per cent, or 1 in 69. "In particular the knowledge of risk with newer progestins was sparse". By contrast, there was no increased risk for breast cancer seen in women who used hormones for less than one year.

But by using computer databases from national health systems, which in Denmark are comprehensive, researchers can look at years of patient data far more cheaply, and with no risk of losing contact.

In Denmark, older women who have completed their families are most likely to use IUDs, including those containing hormones, and they are already more likely to develop breast cancer because of their age, Mørch said.

Not only that, but there are plenty of non-hormonal birth control options to consider, like the non-hormonal IUD, diaphragm and condoms - and let's not forget vasectomies.